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Superfamily Rutoceratoidea Hyatt, 1884 (Pragian to Frasnian, Devonian) includes nautiloid cephalopods havingexogastric cyrtoceracone or coiled shells with periodic walls or raised growth lines (megastriae) forming ridges, some-times modified in various ways into collars, frills, or different outgrowths. High disparity and intraspecific variability ofthe shell form and sculpture of the rutoceratoids are conspicuous among Early Palaeozoic nautiloids. Consequently,rutoceratoids are divided according to different patterns of growth structures into three families. Parauloceratidae fam.nov. (Pragian to Emsian) contains taxa with cyrtoceracone shells and simple recurrent ribs with ventral sinus. FamilyHercoceratidae Hyatt, 1884 (Pragian to Givetian) comprises forms with periodically raised ridges with three lobes form-ing ventrolateral outgrowths during shell growth such as wings, nodes or spines. Family Rutoceratidae Hyatt, 1884(Pragian to Frasnian) encompases taxa having growth ridges with ventral lobe transforming into undulated frills or dis-tinct periodic collars (megastriae). All of these families had already appeared during early radiation of rutoceratoids inthe Pragian. The early radiation of rutoceratoids is, however, adequately recorded only from the Prague Basin.Rutoceratoids become widespread within faunas of Old World and Eastern American realms later during the Emsian andespecially Middle Devonian. Three new genera are erected: Parauloceras gen. nov., Otomaroceras gen. nov. andPseudorutoceras gen. nov. The Pragian Gyroceras annulatum Barrande, 1865 is assigned to the genus AphyctocerasZhuravleva, 1974. Rutoceratoids are thus represented by seven genera and eight species in the Pragian Stage of thePrague Basin. In addition, variability of shell coiling among rutoceratoids and its significance for their systematics arediscussed. • Key words: Nautiloidea, Oncocerida, Rutoceratoidea, Pragian, new taxa, shell morphology.

MANDA, Š. & TUREK, V. 2009. Revision of the Pragian Rutoceratoidea Hyatt, 1884 (Nautiloidea, Oncocerida) from thePrague Basin. Bulletin of Geosciences 84(1), 127–148 (13 figures). Czech Geological Survey, Prague. ISSN 1214-1119.Manuscript received December 12, 2008; accepted in revised form February 13, 2009; published online March 10, 2009;issued March 31, 2009.

Štěpán Manda, Czech Geological Survey, P.O.B. 85, Praha 011, 118 21, Czech Republic; stepan.manda@geology.cz •Vojtěch Turek, National Museum, Department of Palaeontology, Václavské náměstí 68, 115 79 Praha 1, Czech Repub-lic; vojtech.turek@nm.cz

Like everywhere, cephalopod faunas of the Prague Basinwere strongly affected by the extinction at the Silur-ian-Devonian boundary (one order, one suborder and atlast nine families disappeared, see Marek & Turek in Křížet al. 1986; Kříž 1998; Manda 2001, 2007). The subsequ-ent diversification of cephalopods from the late Lochko-vian to the early Pragian, during which several clades origi-nated, remains poorly understood (Manda 2001, Turek2007, Kröger 2008).

Late Lochkovian strata of the Prague Basin containslow diversified and poorly preserved cephalopods: ortho-cerids, pseudorthocerids and oncocerids (Novák 1886,Manda 2001). Cephalopods become a common componentin the Pragian faunas in the Prague Basin. The cephalopodfaunas of the Pragian of the Prague Basin consist of overfifty described species, representing the most diversifiedPragian cephalopod fauna currently known (Barrande

1865–1877, Katzer 1895, Manda 2001, Turek 2007). Mostof the cephalopod taxa were previously described and illus-trated by Barrande (1865–1877), the vast majority of whichhave not yet been revised. The most prominent componentsof the Pragian cephalopod faunas consist of longicone ortho-cerids and pseudorthocerids. Nautiloids, with few excep-tions, occur rarely. Among nautiloids, the oncocerids exhibitthe highest diversity and disparity, while discosorids are rep-resented by few taxa, and tarphycerids of the suborderBarrandeocerina by only a single species (Manda 2001).

The oldest known members of the families Nephriti-ceratidae Hyatt, 1894, Rutoceratidae Hyatt, 1884, Hercoce-ratidae Hyatt, 1884 and Entimoceratidae Zhuravleva, 1972have been described from the Prague Basin. Eleven generahave been based on species from the Bohemian Pragian:Trochoceras Barrande, 1848; Ptyssoceras Hyatt, 1884;Ptenoceras Hyatt, 1894; Gonatocyrtoceras Foerste, 1926;

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Cayugoceras Flower, 1947; Sthenoceras Flower, 1957 (inFlower & Teichert 1957); Zooceras Zhuravleva, 1972;Calorthoceras Chen, 1981 (in Chen et al. 1981); Bohemo-jovellania Manda, 2001; Thalesoceras Manda, 2001 andSuloceras Manda, 2001. However, some of the genera listedabove, as well as generic assignments of Barrande’s speciesmade by Hyatt (1883–1884, 1894), Zhuravleva (1972, 1974,1978), Gnoli (1982), Dzik (1984), Manda (2001) and others,urgently need revision. It should be noted that the illustra-

tions published by Barrande (1865–1877), although excel-lent in quality, sometimes contain Barrande’s “interpreta-tion”; in fact, important details may be missing from some ofhis figures (see Fig. 7). Consequently, conclusions based ex-clusively on Barrande’s published figures may be open todoubt or even wrong. Rutoceratoids from the Pragian of thePrague Basin were partly revised by Manda (2001) andTurek (2007). The remaining species are described and dis-cussed in detail in this paper.

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!������" Distribution of the Pragian rocks in the Prague Basin and position of the mentioned sections (after Havlíček & Vaněk 1998, Röhlich 2007).• Notes on localities: Braník, Barrande’s locality Branik G-g1, most probably a small quarry SSE of the Braník Rock, weathered lower part of theDvorce-Prokop Limestone, earlier Pragian; Parauloceras pupus, Ptenoceras alatum, Michelinoceras sp., Kopaninoceras barbarum, Suloceraspulchrum, Cancellspyroceras loricatum a.o. • Branžovy Quarry, early Pragian (for detail see Fig. 3). • Císařský Quarry, upper part of the KoněprusyLimestone, Pragian (Chlupáč 1955); Otomaroceras tardum, Ptenoceras alatum, Suloceras pulchrum, Spyroceras patronus a.o. • Černá Gorge,Barrande’s locality Kosorz and Lochkov G-g1, lower part of Dvorce-Prokop Limestone, early Pragian (Chlupáč 1957, 1983); Ptenoceras alatum,Aphyctoceras annulatum, Michelinoceras sp., Kopaninoceras barbarum, Suloceras pulchrum a.o. • Červený Quarry, weathered muddy limestone,Dvorce-Prokop or Loděnice Limestone, middle Pragian (Růžička 1941, Havlíček & Vaněk 1998); Pseudorutoceras sp., Goldringia gondola, othercephalopods un-revised. • Damil Hill, Barrande’s locality Damil or Tetin G-g1, exsact site unknown, upper part of the Dvorce-Prokop Limestone(Chlupáč 1983); Otomaroceras tardum, O. flexum, Ptyssoceras alienum, Goldringia gondola, Spyroceras patronus, Michelinoceras sp., Kopaninocerasbarbarum a.o. • Houbův Quarry, upper part of the crinoidal Koněprusy Limestone (Chlupáč 1955, Havlíček & Vaněk 1998); Ptenoceras alatum,Otomaroceras flexum, Trochoceras davidsoni, Spyroceras patronus, Calorthoceras pseudocalamiteum, Dawsonocerina discretum, “Orthoceras”woodwardi a.o. • Homolák Quarry, Koněprusy Limestone, Pragian (Havlíček & Vaněk 1998); Otomaroceras tardum, Ptenoceras alatum, Suloceraspulchrum, Spyroceras patronus, Naedyceras branzovensis a.o. • Malá Chuchle, old quarry in the Malá Chuchle Valley, Dvorce-Prokop Limestone, mid-dle Pragian; Pseudorutoceras sp., Spyroceras patronus a.o. • Srbsko, Šary’s locality, exact site unknown, most probably outcrops in the Berounka Valley,Dvorce-Prokop Limestone, late Pragian; Otomaroceras tardum. • Stydlé Vody Quarry, Dvorce-Prokop Limestone, late Pragian (Chlupáč in Chlupáč ed.1986); Otomaroceras tardum, Spyroceras patronus, Michelinoceras sp., Kopaninoceras barbarum a.o. • Svatý Prokop Quarry, weathered Dvorce-Prokop Limestone (“yellow bed”), late Pragian (Růžička 1941); Goldringia gondola, Spyroceras patronus, Spyroceras sp., Thalesoceras amaltheum.• Voskop Quarry, a large active quarry mining Koněprusy Limestone, Pragian; Otomaroceras flexum, Ptenoceras alatum, Suloceras pulchrum.

We use Pragian stage in its original sense (see Chlupáč1982). By the new definition of the base of the Emsian atthe FAD of Polygnathus dehiscens (GSSP Zinzilban, seeYolkin et al. 1997), a prominent part of the former Pragianwas included in the Emsian. Consequently, some authors(for summary see Carls et al. 2008) have suggested thatbase of the Emsian needs redefining. Note that the exactposition of the base of the Emsian in terms of the currentdefinition in the Prague Basin and peri-Gondwanan Europeis unclear due to missing index taxa.

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At least seven genera and eight species from the Pragianstrata of the Prague Basin are attributed to the rutoceratoids(Figs 1–3). The Pragian Ptenoceras alatum (Barrande,1865) and Ptyssoceras alienum (Barrande, 1865) werepreviously assigned to the rutoceratoids by Kummel(1964). Manda (2001) described the oldest known speciesof Goldringia Flower, 1945, G. gondola Manda, 2001,from the late Pragian Dvorce-Prokop Limestone. Turek(2007) also reported the latter species from the earliest Zlí-chovian (Emsian) strata of the Prague Basin (see Fig. 13A).

Some other Pragian rutoceratoids are described in thispaper. The new genus Parauloceras gen. nov. is based onCyrtoceras pupus Barrande, 1887, previously assigned byManda (2001) to the genus Uloceras Zhuravleva, 1974, ofthe family Trochoceratidae Zittel, 1884. The presence ofdistinct ribs suggests that it in fact belongs to the Ruto-

ceratoidea Hyatt, 1884. The juvenile shell of Parauloceraspupus differs from other rutoceratoids (i.e. Rutoceratidaeand Hercoceratidae), and thus the new family Paraulo-ceratidae is proposed to include rutoceratoids with rela-tively simple shell morphology.

The Bohemian species Trochoceras flexum Barrande,1865 and Trochoceras tardum Barrande, 1865 were as-signed by Hyatt (1894) to the genus Ptenoceras. Zhu-ravleva (1974) considered these species to be ruto-ceratoids, but she listed these species without indicatingtheir generic assignment. Examination of some previouslyunknown specimens of T. flexum as well as T. tardum sug-gests that they represent an independent clade within thehercoceratids and thus Otomaroceras gen. nov. is intro-duced based on Trochoceras flexum.

Pseudorutoceras gen. nov. is based on the late EmsianCyrtoceras bolli Barrande, 1866 from the Prague Basin.Pseudorutoceras sp. is described from two shell fragmentsfrom the Pragian Dvorce-Prokop Limestone; one of which,Manda (2001) previously incorrectly regarded as Gold-ringia gondola. Gyroceras annulatum (Barrande, 1865) isre-described and transferred to the genus AphyctocerasZhuravleva, 1974.

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Two known species of Otomaroceras gen. nov. sharegrowth ridges (megastriae) with three distinct lobes. Oto-maroceras tardum has an almost planispiral shells while

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!�����%" Facies development of the Pragian Praha Formation (modified after Chlupáč 1998) and distribution of rutoceratoids.

Otomaroceras flexum exhibits a helicoid shell. We suggestthat the mode of coiling and subsequent change in shellsymmetry was rapidly changing during evolution and thusdoes not represent a very important diagnostic character.Hyatt (1883–1884, 1894), Flower (1945) and Zhuravleva(1974) overemphasised the taxonomic value of minor dif-ferences in the mode of shell coiling and used these diffe-rences to establish new genera of rutoceratoids. Turek(2007) noted that the intraspecific variability in shell coi-ling ranged from gyrocones to very low torticones (bothsinistrally or dextrally coiled) in the Pragian PtenocerasHyatt, 1894 and the late Emsian Hercoceras Barrande,1865, and consequently he synonymised some taxa thathad been established based on minor differences in coiling.In contrast to the rutoceratoids, the majority of other onco-cerids display rather low variability in shell shape. Thenautiloid orders Nautilida Agassiz, 1847 and TarphyceridaFlower, 1950 exhibit only slow changes in shell coiling du-ring their evolution (e.g., Sweet 1964, Kummel 1964).

The high evolutionary disparity and intraspecific vari-ability of shell coiling in rutoceratoids are remarkable. Itshould be noted that the morphological plasticity of shellform in respect to the mode of coiling in rutoceratoids repre-sents an evolutionary novelty enabling adaptation to a vari-ety of niches, and thus enhancing the evolutionary success ofrutoceratoids during the Early Devonian. Almost all cepha-lopod clades, including species with coiled or curved shells,disappeared or were strongly impoverished by the Silur-ian-Devonian boundary event. Surviving groups rediver-sified and new clades originated in the Early Devonian.

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Raup (1966) analyzed the theoretical morphospace for mol-lusc shells. However, real ectocochliate cephalopods do notpopulate the whole of this morphospace, but are unevenlydistributed within it. The geometrical form of the shellshould be constrained by other factors. Early Palaeozoic(Cambrian–Devonian) nautiloids occupied a wide range ofmorphospaces; however, post Early Palaeozoic ectocochli-ate cephalopods, with the exception of heteromorph ammo-nites, were largely limited to planispiral shells.

The dominance of these morphotypes may be ex-plained by their hydrostatic properties (buoyancy andpoise) and hydrodynamic properties, and how these af-fected swimming. Nevertheless, it is remarkable that theseshell forms did not prevail during the Early Palaeozoicwhen nautiloids with planispiral or nautilicone shells hadalready appeared.

Of the Early Palaeozoic cephalopods with coiled shells,the majority of them are bilaterally symmetrical, i.e. theconch axis is coiled in a single plane. Tarphycerids and

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!�����(" Early Pragian deepening up sequence exposed in BranžovyQuarry, earliest Pragian corresponds with low stand followed by trans-gressive tract. An instructive example of cephalopod succession in thePragian strata of the Prague Basin. Note facial dependence of cephalopodsand restriction of diverse cephalopod assemblages to relatively thin levels.Most diverse assemblage occurs in coarse grainstones filling submarinedepressions close to mud-mounds (see E). Only few cephalopods exhibitcontinuous distribution across the sequence, namely pelagic orthocerids(Kopaninoceras, Michelinoceras) and nectobenthic pseudorthocerid Pseu-docycloceras. • A – platy grey wackestone. • B – massive white limestonewith thin cross-bedded levels of the trilobite packstone filling small subma-rine depressions and channels (mud-mounds). • C – erosive surface of theKoněprusy Limestone, neptunian dykes. • D – coarse cross-bedded trilobitepackstone of the Slivenec Limestone (Platypeltis-Kolihapeltis Assem-blage, fauna from this bed was described by Chlupáč & Šnajdr in 1990).• E – white coarse trilobite-gastropod grainstones with cryptalgal structuresfilling shallow submarine depressions, gastropod fauna was described byHorný (1995). • F – white-grey massive limestone, local accumulations ofbioclasts (mud-mounds). • G – platy grey fine-grained mudstone-wacke-stone. • H – thinly bedded reddish and grey fine-grained wackestone withlarge cephalopod shell. After unpublished data of Š. Manda and J. Frýda.Abbreviations. L. – Lochkovian; K. – Kotýs Limestone, Kop. – Kopa-ninoceras.

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oncocerids exhibited such shells. Nevertheless, shallowtorticonic shells in which the translation of the conch axisin the third dimension is so low that only the outermostwhorl is visible in a ventral view (crypto-torticonic) may befound in the tarphycerids of the suborder Barrandeocerina(e.g., Lechritrochoceratidae Flower, 1950, Nephriticera-tidae Hyatt, 1894) and the oncocerids (HercoceratidaeHyatt, 1884). Nautiloids with planispiral shells were moreor less actively forward swimming animals with the shell ina vertical position and the aperture oriented anteriorly(Westerman 1998). A small deviation of the conch axisfrom the plane of coiling probably does not affect such amode of life. This is corroborated by the high intraspecificvariability in shell coiling reported in the PragianPtenoceras Hyatt, 1894 or the Ludfordian lechritrocho-cerid Kosovoceras Turek, 1975 (Turek 1975, 2007).

Only a few genera belonging to the suborderBarrandeocerina have torticonic shells in which the whorlsare in contact and invisible from the posterior view (e.g.,Lechritrochoceras Foerste, 1930a, Magdoceras Turek,1976, Sphyradoceras Hyatt, 1884). The mode of life of thesenautiloids is largely unknown. Westermann (1998) sug-gested that shallow-torticonic shells have low stability andsuggested a planktonic mode of life for them, but furtherstudies to test this hypothesis are needed. Nevertheless,nautiloids with shallow-torticonic shells usually exhibit asmall area of dispersion as well as facial dependence, whichcontradicts this supposed planktonic mode of life.

The oncocerid Foersteoceras turbinatum Hall, 1852with a high-torticonic shell was described from the middleSilurian of New York. There is some apparent confusion inrelation to this genus. All figured specimens (Grabau 1910,Ruedemann 1925) are poorly preserved. The reconstruc-

tion published by Ruedemann (1925, pl. 21, fig. 1) andrefigured in the “Treatise” by Sweet (1964, K298,fig. 212.2) appears to be an “artistic” rendering rather thanrepresenting the actual form as should be seen in the fig-ured specimens (see Grabau 1910: pl. 31, fig. 3;Ruedemann 1925: pl. 19, fig. 1, pl. 20, fig. 1, pl. 21, fig. 2).

The shell of Otomaroceras flexum is torticonic andloosely coiled. Among cephalopods, similar shell formsare almost completely restricted to heteromorphicammonoids. Shells described here are termed helicoid, andArkell et al. (1957, p. L4) defined this form as “coiled inregular 3-dimensional spiral form with constant spiral angle,as in most gastropods”. Amongst nautiloids this morphotypeis otherwise only known in Lorieroceras lorieri (Barrande,1870) from the Devonian of France (see also Foerste 1926).The only known specimen is a part of a large shell with twowhorls that are not in contact. The mode of coiling of the ju-venile part of the shell is unknown and thus the overall shellmorphology is insufficiently known. Therefore, Otomaro-ceras flexum and perhaps Lorieroceras represent the onlyexamples of nautiloid cephalopods possessing fully helicoidshells. In summary, high torticonic or helicoid shells areknown only in the oncocerids Otomaroceras gen. nov.(Hercoceratidae Hyatt, 1884), Lorieroceras (Nothocerati-dae Fischer, 1882) and perhaps Foersteoceras Ruedemann,1925 (“Brevicoceratidae” Flower, 1941). All of these generaare monospecific, exceptionally rare, and were probably en-demic.

The majority of nautiloids are probably constrained toplanispiral coiling because post-hatching nautiloids havebilaterally symmetrical shells. Thus, the transition fromplanispiral coiling to the 3-dimensional spire has to takeplace through shell transformation after hatching. Helicoid

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!������" Distribution of the Pragian rutoceratoids of the Prague Basin in relation to the facies (depth) zones. • A – reef core limestone (KoněprusyLimestone s.s.). • B – mud-mounds. • C – eroded Lochkovian Kotýs Limestone functioned as submarine cliffs during the earliest Pragian. • D – white-greycoarse cross-bedded crinoid limestone (Koněprusy Limestone s.s.). • E – white grey, grey and reddish crinoid limestone (Koněprusy Limestone s.l.,Slivenec Limestone). • F – thinly bedded biomicritic limestone with thin skeletal (mostly crinoids) accumulations (Loděnice Limestone). • G – grey platytrilobite wackestone (Dvorce-Prokop Limestone, Odontochile-Prokopia Biofacies sensu Havlíček & Vaněk 1998). • H – grey platy mudstone withtentaculites and pelagic orthocerids (Dvorce-Prokop and Řeporyje limestones).

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or highly torticone “gastropod-like” shells were probablyless suitable for active horizontal swimming. The shape ofthe shell, however, could have been favourable for foodcaptures on the sea floor owing to the downward orienta-tion of the aperture (see Westermann 1998). However, themajority of early Palaeozoic nautiloids were bilaterallysymmetrical brevicones and cyrtocones with more or lessdownward oriented apertures. Thus, it is possible that highcompetitive pressure acted as a barrier to the developmentof nautiloids with helicoid shells.

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Morphological terminology is largely adopted from the“Treatise on invertebrate paleontology” (Teichert 1964).The terms height, width and length are used as definedby Stridsberg (1985). For the terminology of growth struc-tures see Fig. 5. All specimens except those figured inFigs 9K–M, 11C, F and 13A were coated with ammoniumchloride prior to photographing.

Institutional abbreviations. – Studied specimens are depo-sited in the Czech Geological Survey, Praha, collections ofŠ. Manda (prefix CGU SM), Palaeontological collection(prefix CGU p); National Museum, Praha (prefix NM L);and Museum of Comparative Zoology, Harvard Univer-sity, Cambridge (prefix MCZ).

Subclass Nautiloidea Agassiz, 1847Order Oncocerida Flower, 1950Superfamily Rutoceratoidea Hyatt, 1884

Diagnosis (emended). – Oncocerids possessing a nearlystraight, cyrtoceraconic or coiled exogastric shell, circularor depressed in cross section. Siphuncle tubular, situatedventrally or sub-ventrally, usually empty or with poorly de-veloped actinosiphonate deposits; septal necks short. Sutu-res simple. Sculpture consists of recurrent growth ridges,which are frequently transformed during shell growth intospectacular outgrowths; oncocerid type of muscle scars.

Discussion. – All taxa grouped within the superfamily Ru-toceratoidea share distinct and variously modified growthridges or ribs, i.e. megastriae (Fig. 5). Simple growth rid-ges are present in the representatives of the family Paraulo-ceratidae. Periodically accentuated growth lines in Rutoce-ratidae are transformed into collars or undulated frillsaround the whole shell. In Hercoceratidae the recurrentemphasized growth ridges changed during ontogeny intoauricle-like, spine-like or wing-like ventrolateral out-growths. The aperture in fully grown shells may be widelyopened or constricted. Intraspecific variability of the shellform, shape of aperture and outgrowths of the shell is high(Fig. 6). Rapidly changing shell morphology in Rutocera-toidea contrasted with a relatively low rate of change insiphuncle morphology (position, diameter, shape of septalnecks and connecting rings).

Three issues concerning rutoceratoids need to be re-solved: (1) the monophyly of rutoceratoids, (2) their affin-ity to the orders Nautilida and Oncocerida, respectively,and (3) their taxonomic ranks.

1. Monophyly of rutoceratoids . – In the originalconcept of Hyatt (1884, 1894, 1900), representatives ofthe superfamily Rutoceratoidea (as considered here) wereplaced within two superfamilies of the suborder Ortho-choanites. Ruzhentsev et al. (1962), Zhuravleva (1974)and Dzik (1984) followed Hyatt’s concept of two inde-pendent clades and placed the family Rutoceratidaewithin the Oncocerida and the family Hercoceratidae(= Trochoceratidae Zittel, 1884) within the Nautilida.By contrast, Flower (1950, 1955) and Kummel (1964)considered the rutoceratoids as a monophyletic group,and this concept is followed here. Similarly, Dzik& Korn (1992) suggested a common ancestor for theHalloceras, Hercoceras and Ptenoceras groups (i.e.rutoceratoids).

2 . Posi t ion of rutoceratoids . – As noted above,Ruzhentsev et al. (1962), Zhuravleva (1974) and Dzik(1984) placed the family Hercoceratidae in the NautilidaAgassiz, 1847 and family Ptenoceratidae (Rutoceratidae inDzik) in the Oncocerida. Kummel (1964) considered allrutoceratids to be nautilids.

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!�����*" Classification of growth structures among rutoceratoids.

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R.H. Flower, in various papers, suggested rutoceratidswere oncocerids or an independent order from which thenautilids diverged (e.g., Flower 1950, 1955, 1964, 1988).Dzik & Korn (1992), Manda (2001) and Turek (2007) con-cluded that the position of all rutoceratoids within the orderOncocerida is supported by the presence of a ventralsiphuncle, cup-like embryonic shell without nepionic con-striction, annular elevation with multiple paired musclescars and the frequent occurrence of modified apertures infully-grown specimens.

3. Taxonomic rank. – Various authors have classi-fied rutoceratoids as family, super-family, sub-order andorder rank taxon. The rutoceratoid material from thePragian strata of the Prague Basin nevertheless shows thatat last three major clades may be distinguished within the“Rutoceratidae” in Kummel’s concept (1964). Conse-quently, the two families proposed by Hyatt (1884, 1894)are accepted here and grouped together with the new fam-ily Parauloceratidae into the superfamily Rutoceratoidea.The relationship of rutoceratoids to the Middle Devoniannautilid Centroceras Hyatt, 1884 (see Flower 1952) andthe Late Palaeozoic nautilids is doubtful. Consequently,the grouping of rutoceratoids with them in the order Ruto-ceratida Flower, 1950 or suborder Rutoceratoidea Hyatt,1884 is thus questionable.

Families included. – Hercoceratidae Hyatt, 1884 (Prag-

ian-Givetian), Rutoceratidae Hyatt, 1884 (Pragian-Frasnian) and Parauloceratidae fam. nov. (Pragian-Emsian). Family Trochoceratidae Zittel, 1884 (see Dzik1984) perhaps also belongs to the superfamily Rutoceratoi-dea, but revision of the type species T. davidsoni Barrande,1865 is necessary to resolve this problem.

Family Parauloceratidae fam. nov.

Diagnosis. – Shell cyrtoceracone, exogastric, exhibitingmarked changes in morphology during shell growth, juve-nile shell is less curved than adult portion. Intrasiphonaldeposits present, but disappear in later growth stages. Pro-minent growth ribs with ventral lobe present in fullygrown shells.

Discussion. – Parauloceras pupus is characterised by adistinct change in shell morphology during shell growth.The juvenile shell is moderately curved, smooth or withfine growth lines. In contrast, the adult shell exhibits dis-tinct growth ridges, which are intercalated with simplegrowth lines. The ribbed adult shell strongly resemblesshells of other rutoceratids in which growth ridges in earlyshells were later transformed in various ways. Thus, the Pa-rauloceratidae are here considered to form the basal cladeof rutoceratoids.

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!�����+" The Pragian-Emsian radation of the rutoceratoids in the Prague Basin. Note that in the latest Pragian, and especially in the early Emsian,rutoceratoids migrated into other regions of the Old World Realm (Baltica, Laurentia). Some poorly known genera (e.g., late Emsian AdelphocerasBarrande, 1870 from the Prague Basin) as well as the Emsian genera recorded outside the Prague Basin are not considered.

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Genera included. – Parauloceras gen. nov. (Pragian-Emsian), Uloceras Zhuravleva, 1974 (Emsian).

Genus Parauloceras gen. nov.

Type species. – Cyrtoceras pupus Barrande, 1877. EarlyDevonian, Pragian, Prague Basin.

Diagnosis. – Rutoceratoid with slightly curved exogastricshell, early shell smooth, fully-grown shell with regulartransversal ribs in body chamber.

Name. – Combination of the Latin prefix para- and thegenus name Uloceras.

Discussion. – Manda (2001) assigned Cyrtoceras pupus tothe genus Uloceras Zhuravleva, 1974. The type species ofthis genus Uloceras insperatum Zhuravleva, 1974 comesfrom the Emsian of the Pechora River Basin. Cyrtoceras pu-pus differs from the type species Uloceras insperatum in ha-ving a more complex morphology. Uloceras insperatum ex-hibits a slightly curved shell with regular transverse ribs thatare sub-quadrate in cross section. Their distance is, however,markedly higher than in U. pupus. The hyponomic sinus isshallower, septa more convex, and siphonal tube narrower.

Species included. – In the Devonian strata of the Prague Ba-sin, Parauloceras is represented by an evolutionary lineagecontaining two closely related species; Parauloceras pupus

(Barrande, 1877) from the Pragian, and Parauloceras sp.nov. (= Cyrtoceras pupus in Barrande 1877, pl. 464, figs8–10) from the Upper Emsian Třebotov Limestone.

Parauloceras pupus (Barrande, 1877)Figure 8A–D

1877 Cyrtoceras pupus Barr.; Barrande, pl. 464, figs 5–7(non figs 8–10; = Uloceras sp. nov.).

1877 Cyrtoceras nepotulus Barr.; Barrande, pl. 465,figs 13–20.

1877 Cyrtoceras pupus Barrande; Barrande, pp. 41, 42.1877 Cyrtoceras nepotulus Barrande; Barrande, pp. 35, 36.2001 Uloceras pupus (Barrande, 1877). – Manda, pp. 270,

271, pl. 1, figs 2–5; text-fig. 1.

Lectotype. – A specimen figured by Barrande (1877) onpl. 464 as figs 5–7 (specimen designated by Manda 2001,NM L 21502).

Type locality. – Praha-Braník (Prague Basin, Bohemia).

Type horizont. – Dvorce-Prokop Limestone, Praha Forma-tion, Early Pragian strata.

Material. – Five specimens, NM L21502, NM L13795,NM L13796, CGS SM3, one specimen (5429) is depositedin Palaeontological Collection, Faculty of Science, CharlesUniversity.

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!�����," Ptyssoceras alienum (Barrande, 1866). • A, B – Holotype, lateral (dextral) and ventral views; × 1.1; NM L 40507, Damil Hill near Tetin; latePragian; Dvorce-Prokop Limestone. • C, D – the same specimen, lateral (sinistral) and ventral views, adopted from Barrande (1866), pl. 127, figs 1, 2.

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Description. – See Manda (2001), pp. 270, 271.

Occurrence. – Early Devonian, lower-middle Pragian.Braník, lower part of the Pragian Dvorce-Prokop Lime-stone, grey wackestone. Section Branžovy, middle Pra-gian, Loděnice Limestone, coarse grainstone (CGS SM 3).

Family Hercoceratidae Hyatt, 1884(syn. Ptenoceratidae Teichert, 1939)

Diagnosis (emended). – Exogastric cyrtoconic to coiledshells, possessing recurrent growth ridges with ventral lobeand two sub-lateral lobes. Ridges may pass into differentoutgrowths such as auricles, wings, spines or nodes duringontogeny. Cross section depressed, siphuncle subventral,thin to moderately wide, without intrasiphonal deposits.

Discussion. – Three genera of the Hercoceratidae are knownfrom the Pragian of the Prague Basin: Ptenoceras Hyatt,1894, Ptyssoceras Hyatt, 1884 and Otomaroceras gen. nov.These genera also represent the oldest known members ofthe family.

Barrande (1865) and Turek (2007) examined about onehundred specimens of Ptenoceras alatum. The protoconchis cup-like and possesses fine straight growth lines(Fig. 12B–D). Shallow hyponomic sinus and lateral lobesappear just after the embryonic chamber. Later in ontogeny,the growth lines become differentiated into two orders andrecurrent raised growth ridges appear (i.e. megastriae). Sub-sequently these marked ridges form ventrolateral lobes. Oneor two characteristic wings appeared near the aperture offully-grown shells. In late Emsian Hercoceras ventrolateralauricles (wings) appear in the juvenile shell (Fig. 12G) andare usually transformed into hollow spines during shellgrowth. The line of Ptenoceras-Hercoceras clearly exhibitsan evolutionary trend from loosely to closely coiled shells(Manda 2001, Turek 2007) and the extension of lateral out-growths (Dzik & Korn 1992). These lateral outgrowths mayrepresent a selective advantage in hercocerids.

Ptyssoceras alienum (Barrande, 1865), based on theholotype only (Fig. 7), probably possessed a cyrto-ceraconic shell with elongated, ventrolaterally situatedV-shaped nodes. The cross section of the shell is slightlydepressed, and the siphuncle is ventral. In cross-section,the position of the siphuncle in Ptyssoceras resemblesPtenoceras. Additionally, the elongated nodes are similarin shape to the lobes on raised ridges in Ptenoceras. Thus,both genera probably shared a common ancestor.

The new genus Otomaroceras shares similar typesof growth ridges with three lobes with Ptenoceras. Oto-maroceras, however, differs in having ridges without out-growths, while recurrent growth ridges appeared later dur-ing ontogeny and the distance between them is greater.

The whorl cross-section is less depressed than that ofPtenoceras.

Ordovician and Silurian oncocerids usually exhibit abilaterally symmetrical shell with circular, sub-circular orcompressed elliptical shell cross-sections. The Devonianhercoceratids show sub-circular or more commonly de-pressed cross-sections, which are usually elliptical,quadrate or even sub-polygonal. In addition, the cross-sec-tion is often slightly asymmetrical as the shell is weaklyturned to the left or less frequently to the right from theplane of symmetry. A similar morphological trend in thelateral extension of the shell is achieved in some other De-vonian nautiloid clades, e.g. in the Entimoceratidae (seeZhuravleva 1972). Lateral extension of the shell mighthave improved stability during swimming and jet propul-sion. Similarly, the recurrent growth ridges may have actedto modify turbulence and change drag during swimming.

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!������" Parauloceras pupus (Barrande, 1877). • A, B – ventral and lat-eral views (a specimen figured by Barrande on pl. 465, figs 13–16 as“Cyrtoceras nepotulus” Barrande, 1877); × 1; NM L 13795; Braník local-ity, Early Pragian; Dvorce-Prokop Limestone. • C, D–- ventral (× 1.3) andlateral (× 1.2) views, specimen CGS SM 3; ×; Branžovy Section; middlePragian; lowermost Loděnice Limestone. • E, F – ventral and lateralviews; × 1.3; a specimen deposited in the Palaeontological collection ofFaculty of Sciences, Charles University under number 5429; Braník local-ity, early Pragian; Dvorce-Prokop Limestone.

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Genera included. – Ptenoceras Hyatt, 1894 (Pragian-Eifel-ian); Adeloceras Zhuravleva, 1974 (Emsian) [= DolerocerasZhuravleva, 1972; see Turek 2007, p. 9]; Anepheloceras Zhu-ravleva, 1974 (Emsian); Capricornites Zhuravleva, 1974(Emsian); Centrolitoceras Flower, 1945 (Middle Devonian);Diademoceras Flower, 1949 (Emsian); Hercoceras Bar-rande, 1865 (Emsian-Eifelian) [including BastindocerasZhuravleva, 1974 (Eifelian), Piratoceras Zhuravleva, 1974(Emsian) and Spanioceras Zhuravleva, 1974 (Eifelian); ?Me-galoceras Zhuravleva, 1974 (Emsian); Moneroceras Zhurav-leva, 1996 (Emsian); ?Nassauoceras Miller, 1932 (MiddleDevonian)]; Nozemoceras Zhuravleva, 1996 (Emsian); Oto-maroceras gen. nov. (Pragian); Ptyssoceras Hyatt, 1884 (Pra-gian); Pleuronoceras Flower, 1950 (Middle Devonian); newunnamed genus (based on Rutoceras eospinosum Zhuravleva,1974, Emsian of the Pechora River Basin. This unnamed ge-nus possesses recurrent growth ridges with lateral lobes as inPtenoceras, but the shell is only slightly curved).

Genus Otomaroceras gen. nov.

Type species. – Trochoceras flexum Barrande, 1865; EarlyDevonian, Pragian; Bohemia, Prague Basin.

Name. – In honour of the Czech palaeontologist OtomarPravoslav Novák (1851–1892).

Diagnosis. – Oncocerid with open-coiled exogastric shellpossessing recurrent raised growth ridges having three lo-bes – a ventral lobe and two ventro-laterally placed lobes;ridges without outgrowths.

Discussion. – The holotypes of Trochoceras flexum Bar-rande, 1865 and Trochoceras tardum Barrande, 1865 areboth poorly preserved internal moulds. Trochoceras tar-dum was figured by Barrande on pl. 26 as figs 9–12 andTrochoceras flexum on pl. 44 as figs 1–3. Although thesetaxa were described as separate species (see Barrande1867), the figure explanation of Trochoceras tardum Bar-rande, 1865 includes the additional remark that Trochoce-ras flexum is perhaps identical with Trochoceras tardum.They were also considered as separate taxa within thegenus Ptenoceras by Hyatt (1894) and family Ptenocerati-dae Zhuravleva (1974). Further support for this assignmentis given by the raised ridges running around the shell withthree lobes and a quadrate to sub-quadrate cross-section.

Species assigned. – Otomaroceras is so far known only fromthe Pragian strata of the Prague Basin where it is representedby O. flexum Barrande, 1865 and O. tardum Barrande, 1865.

Otomaroceras flexum (Barrande, 1865)Figures 9A–M, 12E

1865 Trochoceras flexum Barr.; pl. 44, figs 1–3.1865 Trochoceras distortum Barr.; pl. 28, figs 11–14.1867 Trochoceras flexum Barrande; p. 99.1867 Trochoceras distortum Barrande; pp. 98, 99.1894 Ptenoceras flexum. – Hyatt, p. 492.1974 T. flexum Barrande. – Zhuravleva, p. 96.1974 T. distortum Barrande. – Zhuravleva, p. 97.

Type. – Holotype by monotypy. An internal mould figuredby Barrande (1865) as figs 1–3 on pl. 44, NM L 246.

Type locality. – Barrande’s locality “Tetin” in the DamilHill area near Beroun, exact site unknown.

Type horizont. – Devonian, Early Devonian, Pragian (Bar-rande’s etage G, bande G-g1).

Material. – Holotype and eight additional specimens (NML 197, NM L 8054, NM L 40502, NM L 40504, SM324–327).

Descriptions. – Helicoid sinistrally coiled exogastric shell,perhaps with two whorls. Angle of expansion is about 10°.Cross-section of the whorl slightly asymmetrical, sub-trapezoidal; ratio of height/width decreases from 1.1 to 0.9with growth. Siphuncle thin, ventral. Length of phragmo-cone chambers is variable; the ratio between shell heightand length of phragmocone chamber varies between 4.5–8.Septa moderately vaulted with maximal depth in the shellaxis. Suture oblique with shallow lateral saddles, ventraland dorsal lobes. Shell surface smooth or with fine and irre-gular growth lines. Recurrent growth ridges exhibit oneventral and two ventrolateral lobes, almost equal in dimen-sion. The width of recurrent growth ridges in fully-grownshell is about 0.6 mm. Distance of adjacent ridges is appro-ximately equal to half of the shell height. Hyponomic sinusis prominent and relatively broad. Length of the bodychamber is approximately twice the shell height. The maxi-mal adapertural shell height is 28 mm.

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!�����1" Otomaroceras flexum (Barrande, 1865). • A, J – lateral and ventral views; holotype NM L 246; × 0.9; Damil Hill near Tetin; late Pragian;Dvorce-Prokop Limestone. • B-D, I – lateral, dorsal and ventral views, cross section, × 1; CGS SM 325; Koněprusy, Houbův Quarry; Pragian; KoněprusyLimestone. • E – ventral view, × 1; NM L 40502; Koněprusy, Voskop Quarry; Koněprusy Limestone. • F–H – lateral (dextral), ventral and lateral(sinistral) views, × 0.9; CGS SM 324; Koněprusy, Houbův Quarry; Pragian; Koněprusy Limestone. K–M – dorsal, lateral and ventral views, × 0.7;NM L X; Damil Hill near Tetin; late Pragian; Dvorce-Prokop Limestone.

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Discussion. – The holotype of Otomaroceras flexum is apoorly preserved slightly corroded internal mould. Never-theless, it exhibits distinct growth ridges with three lobesthat may also be seen in better-preserved specimens in ourrepository; in addition, the mode of coiling is the same.Newly examined relatively complete shells of O. flexumsuggest that “Trochoceras distortum” Barrande, 1865(from the same locality as the holotype of O. flexum)is conspecific with O. flexum because it has a similar shellspire, cross-section, and length of body chamber. Bothof the types of “Trochoceras distortum” are internalmoulds, nevertheless the specimen figured by Barrandeon pl. 28, figs 11, 12 shows imprints of growth ridges(see Fig 12E, note that the growth ridges is not visible inBarrande’s figure) with three lobes similar in shapewith that at O. flexum, which further support the syno-

nymy of O. flexum with “Trochoceras distortum”.[The lectotype of “Trochoceras distortum” is selected he-rein as the specimen figured by Barrande (1865) on pl. 28as figs 13, 14, type locality Tetin, i.e. Damil Hill, Prag-ian.]

Occurrence. – Early Devonian, Pragian; Bohemia, PragueBasin; Praha Formation. Koněprusy Limestone: Koně-prusy, Zlatý Kůň Hill, Houbův Quarry; coarse crinoidallimestone (CGS SM 324, 326). Both specimens were col-lected by J. Bouška from the so-called “yellow beds”, i.e.strongly weathered limestones from which fossils are ob-tained by washing; for exact location and faunal list seeKodym et al. (1931). Koněprusy, Voskop Quarry, lowerpart of Koněprusy Limestone (NM L 40502). Road cut westof the Homolák Quarry at Měňany; coarse trilobite-brachiopod packstone (NM L 40502). Slivenec Limestone:Branžovy Quarry at Loděnice; coarse trilobite packstone,Kolihapeltis Community (CGS SM 325, 327). Dvorce-Prokop Limestone: Damil Hill at Beroun, exact site un-known; grey wackestones.

Otomaroceras tardum (Barrande, 1865)Figures 10 A–D, 11A–I

1865 Trochoceras tardum Barr.; Barrande, pl. 26, figs 9–12.1867 Trochoceras tardum Barrande; Barrande, pp. 101,

102.1894 Ptenoceras tardum. – Hyatt, p. 492.1974 T. tardum Barrande. – Zhuravleva, p. 96.

Type. – NM L 40501. Holotype by monotypy. Figured byBarrande (1865, pl. 26 as figs 9–12, see Fig. 10A, B).

Type locality. – Barrande’s locality “Tetin”, near the DamilHill near Beroun, exact site unknown.

Type horizont. – Devonian, Early Devonian, late Pragian(Barrande’s etage G, bande G-g1 ).

Other material. – Four incomplete shells with broken-offapical portions (NM L40505, NM L 40506, CGS SM 330,MCZ 133261), one shell fragment (CGS SM 329), and twobody chambers (CGS SM 328, CGS p824).

Description. – Gyroceraconic exogastric sinistrally coi-led shell with two whorls. Angle of expansion is about13°. Cross section sub-quadrate, slightly depressed; ratioof height/width is 0.9. Siphuncle relatively thin, marginal.Length of phragmocone chambers is variable, usuallylow. Septa moderately vaulted with maximal depth of theshell axis. Suture is oblique with shallow lateral and ven-tral lobes. Shell surface variable, either almost smooth or

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!������7" Otomaroceras tardum (Barrande, 1865). • A, B – lateraland ventral views; holotype NM L 40501; × 1; Damil Hill near Tetin;late Pragian; Dvorce-Prokop Limestone. • C, D – ventral and lateralviews; CGS SM 390; Damil Hill near Tetin; late Pragian; Dvorce-Prokop Limestone.

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with fine and irregularly arranged growth lines. Recurrentgrowth ridges with three lobes (ridges appear at a shellheight of 25 mm), ventral lobe is shallower than ventrola-teral lobes. Distance between ridges is variable. Hypono-mic sinus relatively broad. Length of body chamber isabout 1/3 of the whorl. Maximum shell height observed is34 mm, width 45 mm. Maximal shell thickness is about1.4 mm.

Discussion. – Comparison of the holotype with other spe-cimens assigned to this species is complicated by the factthat the holotype consists of a poorly preserved internalmould. Five specimens from the old collections are simi-lar to the holotype in their mode of coiling, cross-section,angle of expansion and length of body chamber. We con-sider all these specimens to be conspecific. Differences inshape of lobes at recurrent ridges (i.e. slightly narrowerlateral lobes and shallower ventral lobe in holotype) may

be attributed to changes in lobe morphology during shellgrowth, as well as the mode of preservation. The holotypeis an internal mould, and imprints of growth ridges on in-ternal moulds differ slightly from their traces on the shellsurface. Otomaroceras tardum differs from Otomaroce-ras flexum in having very shallow torticone shell, and thelateral lobes at recurrent ridges are deeper and shiftedslightly ventrally.

Occurrence. – Devonian, Early Devonian, Pragian; PrahaFormation. Koněprusy Limestone: Koněprusy, exact siteunknown (NM L 40505, NM L 40506), Koněprusy, ZlatýKůň Hill, Císařský Quarry (CGS p824); Měňany, HomolákQuarry, road cut approximately 50 m to the west from thequarry (CGS SM 328). Dvorce-Prokop Limestone: Tetín,Damil Hill (holotype, CGS SM 330). Srbsko, exact site un-known (MCZ 133261). Stydlé Vody Quarry near Svatý Janpod Skalou (CGS SM 329).

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!�������" Otomaroceras tardum (Barrande, 1865). • A, B - ventral and lateral views, × 0.6; MCZ 133261; Srbsko; late Pragian; Dvorce-Prokop Lime-stone. • C, G – dorsal and lateral views, × 0.7; NM L 40505; Koněprusy, exact site unknown; Pragian; Koněprusy Limestone. • D, E – lateral and ventralviews, × 0.8; Koněprusy, Císařský Quarry; Pragian; Koněprusy Limestone. • F, H, I – lateral, ventral and dorsal views, × 0.8 (F), 0.9 (H, I); CGS SM 328;Koněprusy, Homolák Quarry; Pragian; Koněprusy Limestone.

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Family Rutoceratidae Hyatt, 1884(syn. Ryticeratidae Hyatt, 1900, Halloceratidae Hyatt,1900, Adelphoceratidae Foerste, 1926)

Diagnosis (emended). – Oncocerids with exogastric cyrto-cone to coiled shell, circular and sub-circular cross-section,growth lines transformed into undulated frills, periodiccollar or annuli around whole shell.

Genera included. – Adelphoceras Barrande, 1870 (lateEmsian); Aphyctoceras Zhuravleva, 1974 (Pragian-Givetian); Capricornites Zhuravleva, 1974 (Emsian); Cas-teroceras Flower, 1936 (Middle Devonian); GoldringiaFlower, 1945 (Pragian-Givetian); Halloceras Hyatt, 1884(Emsian-Givetian); Hindeoceras Flower, 1945 (MiddleDevonian); Homoadelphoceras Foerste, 1926 (Late Em-sian); Kophinoceras Hyatt, 1884 (Middle Devonian);Pseudorutoceras gen. nov. (late Emsian); Rutoceras Hyatt,1884 (Middle Devonian, ?Early Frasnian); TetranodocerasFlower, 1936 (Middle Devonian).

Pseudorutoceras gen. nov.

Type species. – Cyrtoceras bolli Barrande, 1877. Lectotype– the specimen NM L 449 designated here, figured by Bar-rande in 1866 on pl. 119 as figs 5–9, type localityPraha-Hlubočepy, Early Devonian, late Emsian of Bohemia.

Diagnosis. – Oncocerid with slightly curved shell, circularor slightly depressed cross-section, sutures straight and ob-lique to shell axis, shell with distinct undulated frills (wa-ves are almost equal in length and height) around wholeshell; frills, except at the hyponomic lobe almost straightand oblique to shell axis.

Name. – Name is derived from Latin prefix pseudo and ge-neric name Rutoceras.

Discussion. – Pseudorutoceras gen. nov. can be easily re-cognised by the presence of regularly undulated frills on theshell. Dark lines visible on the abraded surface of the lecto-type in the adapical part of the shell were formerly interpre-ted as colour pattern (Foerste 1930b, Kobluk & Mapes1989), an opinion later refuted by Turek (1990, in press).

Species assigned here to the Pseudorutoceras were pre-viously placed in Goldringia Flower, 1945 and RutocerasHyatt, 1884 (e.g., Flower 1945, Zhuravleva 1974, Manda2001). These genera differ from Pseudorutoceras in hav-ing distinct recurrent collars around the whole shell (e.g.,Fig. 13A). The collar is formed from recurrent growthridges developed during early growth stages (for examplesee early shell of Goldringia gondola; Fig. 12H–J).Goldringia and Rutoceras exhibit irregular undulation of

the growth lines, especially on the venter. These undulatinggrowth lines sometimes form structures resembling longi-tudinal ribs because the lobes of these undulations arecloser to each other than the saddles. It is probable thatPseudorutoceras shares a common ancestor with theGoldringia-Rutoceras group (Fig. 6).

Pseudorutoceras sp. from the Pragian of the Prague Ba-sin represents the oldest known species of the new genusPseudorutoceras. The two available specimens are poorlypreserved, but the length of phragmocone chambers andthe character of the undulating frills strongly resemble theyounger species Pseudorutoceras bolli (Barrande, 1866)from the Třebotov Limestone, late Emsian. Both speciesprobably represent a phyletic link from which all MiddleDevonian species of Pseudorutoceras diverged.

Species included. – Pseudorutoceras sp., Pragian, PragueBasin. Pseudorutoceras bolli (Barrande, 1866), late Em-sian, Prague Basin. Pseudorutoceras citum (Hall, 1879),Middle Devonian, New York. Pseudorutoceras cf. citum(Hall, 1879) sensu Fagerstrom (1961), Middle Devonian,SE Ontario. Pseudorutoceras difficile (Whidborne, 1890),Givetian, South England. Pseudorutoceras fimbriatum(Phillips, 1841), Givetian, South England. Pseudorutocerasquindecimale (Phillips, 1841), Givetian, South England.

Pseudorutoceras sp.Figure 12A, F

partim 2001 Goldringia gondola sp. nov.; Manda, pl. 1, fig. 12,p. 273.

Material. – Two shell fragments, NM L 4050, CGS SM 5.

Descriptions. – Specimen CGS SM 5 is a fragment of thephragmocone and part of the body chamber, diameter11 mm, length 21 mm. Shell is slightly curved with circularcross-section. Sculpture characterised by regularly undula-ted frills (1 mm apart). Length of the phragmocone cham-bers is 2 mm. Second available specimen (NM L 4050) is asmall fragment of a large shell, 17.5 × 18 mm. It showswell-developed undulated frills intercalated with parallelundulated growth lines. Distance of frills varies between2–3.5 mm. Distance of growth lines varies slightly, 6 to 11growth lines are visible between each pair of frills.

Discussion. – Pseudorutoceras sp. differs from all otherspecies of the genus in the presence of growth lines bet-ween undulated frills; all other stratigraphically youngerspecies share dense undulated frills similar to those seen inthe juvenile shell of Pseudorutoceras sp. (Fig. 12A). Thus,the periodic growth structures were present in the ancestorof Pseudorutoceras and their reduction in all Emsian and

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Middle Devonian species of Pseudorutoceras represents aderived character state.

Occurrence. – Early Devonian, Pragian, Praha Formation.Dvorce-Prokop Limestone, so-called “yellow beds”, i.e.weathered biomicritic limestones. Praha-Malá Chuchle,old quarry W of the Malá Chuchle and Malá Chuchle Val-ley (CGS SM 5); Praha-Klukovice, Červený Quarry.

Genus Aphyctoceras Zhuravleva, 1974

Type species. – Rutoceras parvulum Kuzmin, 1966. Mid-dle Devonian, Eifelian. Novaya Zemlya.

Discussion. – This genus includes several species knownfrom the Eifelian and Givetian strata of the Old WorldRealm, e.g., England, Germany, Morocco, Novaya Zemlya,Siberia and the Ural Mts. The single body chamber descri-bed by Barrande (1865, pl. 44, figs 4–7) as Gyroceras an-nulatum Barr. shows all diagnostic features of Aphyctoce-ras. Thus, Gyroceras annulatum represents the oldestknown species of Aphyctoceras.

Aphyctoceras annulatum (Barrande, 1865)Figure 13B–D

1865 Gyroceras annulatum Barr.; pl. 44, figs 4–7.1867 Gyroceras annulatum Barr.; p. 163.1957 Ptenoceras(?) annulatum. – Chlupáč, pp. 376, 436.

Holotype. – By monotypy, specimen figured by Barrande(1865) on pl. 44 as figs 4–7, NM L 9089.

Type locality. – After original designation Lochkov G-g1.Exact site unknown, Pragian strata crop out in the ČernáGorge and Radotín Valley SSE from the Praha-LochkovVillage.

Type horizon. – Early Devonian, Pragian, Dvorce-ProkopLimestone, grey muddy limestone.

Description. – Shell cyrtoceraconic and moderately expan-ding, slightly depressed (l/w ratio 0.9). Body chambershort; length of the body chamber exceeds 1.5 times theadapertural width of the shell. Aperture slightly constric-ted. Surface with distinct, transverse, widely spaced annuli

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!������%" A – Pseudorutoceras sp., × 1.8; CGS SM 5; Malá Chuchle; Pragian; Dvorce-Prokop Limestone. • B–D – Ptenoceras alatum (Barrande,1865), ventral, lateral and dorsal views, × 5.4; CGS SM 331; Houbův Quarry; Pragian; Koněprusy Limestone. • E – Otomaroceras flexum (Barrande,1865), lectotype of “Trochoceras distortum” Barrande, 1865, lateral view, × 0.9; NM L 197; Damil Hill near Tetin; late Pragian; Dvorce-ProkopLimestone. • F – Pseudorutoceras sp., lateral view, × 1.7; NM L 4050; Klukovice, Červený Quarry; late Pragian; Dvorce-Prokop or Loděnice Lime-stone. • G – Hercoceras mirum Barrande, 1865, lateral view, × 1.8; CGS SM 337; Holyně (see Bouček 1931), so-called “yellow beds”; latest Emsian.• H–J – Goldringia gondola Manda, 2001, dorsal, lateral and ventral view, × 2; CGS SM 323; Hlubočepy, Svatý Prokop Quarry; late Pragian,Dvorce-Prokop Limestone.

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forming a shallow, slightly acute ventral lobe. Longitudi-nal ribs are very weakly marked on the internal mould.Annular elevation with marked muscle imprints graduallyenlarging laterally from both the ventral and dorsal sides.

Occurrence. – See the holotype.

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Previously unknown or newly examined material of ruto-ceratoids is described from the Pragian of the Prague Ba-sin. This material enabled the evaluation of the classifica-tion of rutoceratoids as well as a revision of somepreviously published opinions concerning rutoceratoidsystematics and the evolution of Devonian nautiloids.

1. Seven genera and eight species of rutoceratoids(Rutoceratoidea) are known from the Pragian of the PragueBasin. Ptenoceras alatum (Barrande, 1865) and Ptysso-ceras alienum (Barrande, 1865) had already been placed inthe rutoceratoids by Kummel (1964). Goldringia gondolawas described by Manda (2001). In this paper, five addi-tional taxa are added to the rutoceratoids: Pseudorutocerassp., Otomaroceras gen. nov. [C. flexum (Barrande, 1865),C. tardum (Barrande, 1865)], Aphyctoceras [A. annulatum(Barrande, 1865)], and Parauloceras gen. nov. [P. pupus(Barrande, 1877)].

2. The genera Ptyssoceras Hyatt, 1884, Paraulocerasgen. nov. and Otomaroceras gen. nov. are at present knownfrom the Prague Basin only. Currently, the earliest knownrepresentatives of the genera Ptenoceras Hyatt, 1894,Aphyctoceras Zhuravleva, 1974, Goldringia Flower, 1945and Pseudorutoceras gen. nov. are from the the Pragian ofthe Prague Basin.

3. Rapid diversification of the superfamily Ruto-ceratoidea took place in the early Pragian (i.e. just after“Basal Pragian Event”, Chlupáč & Kukal 1988). All major

clades of rutoceratoids originated during this radiation, i.e.Parauloceratidae fam. nov., Rutoceratidae Hyatt, 1884 andHercoceratidae Hyatt, 1884 (Fig. 6). The palaeobiogeo-graphical distribution of Pragian rutoceratoids seems to belimited to the Prague Basin area. Only Goldringiavalnevenzis Zhuravleva, 1996 is known from the LatePragian of Novaya Zemlya. However, the major dispersionevents of rutoceratoids happened later during the Emsianand Eifelian, when rutoceratoids became widespreadwithin the faunas of the Old World (Rutoceratidae,Ptenoceratidae) and of Eastern American (Rutoceratidae)realms (Flower 1945).

4. The evolutionary success of the rutoceratoids reflectsa high evolutionary plasticity of their shell form and sculp-ture, enabling adaptation to various environmental set-tings. Rutoceratoids rapidly occupied a variety of nichesranging from extremely shallow reef environments todeeper water settings below the storm wave base (Figs 2, 4).The radiation of ruthoceratids took place after the extinc-tion event at the Silurian-Devonian boundary when manycephalopod clades became extinct (Manda 2001, 2007;Kröger 2008) and may correspond with the filling of vacantniches after this extinction. During the Pragian recovery ofcephalopod faunas, rutoceratoids reached the highest di-versity as well as the highest disparity among coevalnautiloid clades.

5. Rutoceratoids are considered as a monophyleticclade within the order Oncocerida (see Fig. 6). Thesuperfamily Rutoceratoidea is divided into three familiescharacterised by the presence of recurrent growth ridgesand their modifications: Parauloceratidae fam. nov. (sim-ple transversal ribs on adult shell), Hercoceratidae (recur-rent raised growth ridges with three lobes transformed dur-ing ontogeny into ventrolateral outgrowths – auricles orhollow spines) and Rutoceratidae (growth ridges trans-formed into undulated frills or a recurrent collar aroundwhole shell).

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!������(" A – Goldringia gondola Manda, 2001, ventolateral view, × 1; Damil Hill at Tetín, Modrý Quarry; early Emsian (earlier Zlíchovian); ZlíchovFormation. • B–D – Aphyctoceras annulatum (Barrande, 1865), holotype, lateral, ventral and dorsal views, × 1; NM L 9089; Praha Lochov locality; earlyPragian, Dvorce-Prokop Limestone.

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6. The origin of the Rutoceratoidea is unclear (see alsoFlower 1955, p. 254). The shell form and surface sculptureof the vast majority of rutoceratoids differs strongly fromSilurian oncocerids. A possible ancestor may be indicatedby the comparison of the juvenile shell of Parauloceras(Fig. 8), which in our opinion belongs to the basal clade ofthe Rutoceratoidea (Fig. 6). The juvenile shell of Pa-rauloceras pupus is slightly curved, moderately depressedand smooth or with gentle growth lines. The siphuncle ismarginal with cylindrical connecting rings and poorly de-veloped intrasiphonal deposits resembling actinosiphonatedeposits. Intrasiphonal deposits rapidly disappeared duringthe growth of the shell. Thus, the shell of Parauloceras re-sembles early shell of Projovellania Hyatt, 1900 (sensuManda 2001) from the Ludlow–early Lochkovian strata.However, further investigations are needed in order to ver-ify this.

7. The species of the newly established genus Oto-maroceras share distinct recurrent low ridges with threelobes, but strongly differ in shell coiling; O. tardum has analmost planispirally coiled gyroceracone shell while O.flexum has a helicoid shell. These features suggest that dif-ferences in shell coiling might be rapidly fixed during evo-lution and, in fact, do not represent an important diagnosticfeature among rutoceratoids. Similarly, Turek (2007) ex-amined the distinct intraspecific variability of the shellform in Ptenoceras and Hercoceras.

8. The three dimensionally coiled shell is well known inheteromorph ammonoids. Among nautiloids, helicoid orhigh torticone shells are known only in Devonian Lo-rieroceras and perhaps in the Silurian Foersteoceras. Anadditional example is reported with the Pragian Otoma-roceras flexum. The scarcity or absence of helicoid andhigh-torticone shells among nautiloids may be easily ex-plained by an ontogenetic constraint. All nautiloids haveplanispiral shells after hatching. Consequently, shell trans-formation from a 2D to a 3D spire must have occurred dur-ing shell growth immediately after hatching; this transi-tional stage was most probably inconvenient with respectto drag and manoeuvrability.

9. An interesting feature of rutoceratoid diversity pat-tern is the change in diversity of the families Hercoce-ratidae and Rutoceratidae. If we summarise all availabledata, it is clear that the Hercoceratidae are more diverseduring the Early Devonian, and Rutoceratidae duringthe Middle Devonian. The change in the diversity patterncoincides approximately with the Choteč extinction event(Chlupáč & Kukal 1988, House 2002). Since both familiesexhibit similar features (highly elaborated sculpture, shelloutgrowths), the change in the diversity pattern is not easyto attribute to the acquisition of new characters and thus re-mains enigmatic.

10. The Pragian rutoceratoids appear to representsmall, geographically restricted and isolated populations

within the Prague Basin (Figs 2, 3). They inhabited specificbiotopes within carbonate platforms, namely mud-moundsand adjacent areas; settings close to reef cores, and a nar-row zone along the lower slope (lower part of theDvorce-Prokop Limestone overlying Loděnice Limestoneduring deepening). The mosaic distribution of rutoceratoidpalaeo-populations accords well with their rapid radiationand diversity changes.

The maximum diversity of rutoceratoids coincides withthe low stands and the subsequent initiation of deepening inthe early and middle Pragian. It should be noted that in theKoněprusy area at least, late Pragian strata are missing dueto emersion above sea level (Janoušek et al. 2001). The lat-est Pragian muddy limestones deposited during high standconditions contain no rutoceratids. The base of theZlíchovian (Emsian) again coincides with a shallowing andthe reappearance of reefs. Although the brachiopod-bryo-zoan-coral fauna strongly resembles that in Koněprusy reeflimestone (see Havlíček & Vaněk 1998, Chlupáč & Kolář2001, Budil & Kolář 2004), the molluscan fauna is mark-edly reduced in diversity and abundance. Goldringia gon-dola is the only rutoceratid known from the earliestZlíchovian (Zlíchov Limestone, grey fine-grained wacke-stone, Damil Hill; Fig. 13A). The muddy limestones of themiddle to late Zlíchovian carbonate sequence were againdeposited during deepening, and no rutoceratoids havebeen recorded from these strata. Rutoceratoids re-appearedagain in the late Dalejan (latest Emsian) and the majority ofthem are considered as descendents of the Pragian ruto-ceratoids known from the Prague Basin (e.g., Ptenocerasalatum-P. proximum and Hercoceras mirum; Paraulo-ceras pupus-P. sp. nov., Pseudorutoceras sp.-P. bolli).

11. From the palaeobiogeographical point of view therestriction of the Pragian rutoceratoids (as well as someother nautiloid taxa, e.g. Cayugoceras, Gonatocyrtoceras,Nephriticerina, Sthenoceras, Zooceras) to the Prague Ba-sin is remarkable. Although many well-known terrainsexhibit faunal affinities with the Prague Basin (e.g., theCarnic Alps, Harz Mts, Linderer Mark at Giessen, Armori-can Massif, Sardegna, Iberian Chain, Morocco, and theSouth Ural; see Zhuravleva 1972, 1974), no rutoceratoidshave been reported from them. Palaeozoic nautiloids weremore or less nectobenthic animals after hatching (for sum-mary see Chirat & Rioult 1998, Manda 2008). As a conse-quence, their migration routes were restricted to shallowshelves and within shallow platforms. Migration acrossdeep-water seas was possible, but represented ratherlong-term and multiphase processes (Manda 2008).

The Pragian rocks of the Prague Basin probably repre-sent relict of a larger carbonate platform that was isolatedfrom surrounding terrains by deep water, rather than form-ing part of a carbonate shelf. This conclusion further sup-ports the concept of the Perunica microplate (Havlíček etal. 1994), which originated by rifting from the shelf of

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Gondwana in the Ordovician. The Devonian history ofPerunica is poorly known; nevertheless the onset of sili-ciclastic sedimentation in the Givetian documents its ac-cretion to the Old Red Continent (e.g., Kukal & Jager 1988,Chlupáč 1998). The localised radiation of rutoceratoidsduring the Pragian suggests that the Perunica microplatewas still separated from surrounding terrains by a deep seaat this time, which may have functioned as a barrier forsome nectobenthic animals.

12. Signor & Brett (1984) suggested that highly elabo-rated shell sculptures in nautiloids (e.g., spines, wings, col-lars, distinct growth walls) functioned as protection againstpredators and they also pointed out that increasing diver-sity of well-sculptured nautiloids during the Devonian rep-resents an adaptive reaction to the radiation ofdurophagous predators. Appearance and diversification ofrutoceratoids in the Early–Middle Devonian seems to be inagreement with these suggestions. It is interesting thatstrongly sculptured nautiloids morphologically convergentwith rutoceratoids had already appeared in the Ordovicianand Silurian (e.g., Zitteloceras Hyatt, 1884, CorbulocerasHorný, 1965, Torquatoceras Stridsberg, 1988 and severalothers). Moreover, repaired injuries in shells of pre-Devo-nian nautiloids may suggest that there were some predatorsattacking cephalopods in this time. The relative high fre-quency of repaired injuries may further indicate that at-tacks by predators on nautiloids were a more than occa-sional event (and thus documents a relatively highpredation pressure in the Ordovician and Silurian; for datasee Barrande 1865–1877, Kröger 2004, Manda & Turek inpress). If well-sculptured shells represented a predator re-sistant (defensive) feature, the question is then raised as towhy Ordovician and Silurian nautiloids with such shellsculptures represent rare, palaeobiogeographicaly stronglylimited and short-lived nautiloid taxa. We conclude, as didSignor & Brett (1984), that there does not appear to be anyexplanation for the scarcity of well-sculptured nautiloids inthe Ordovician and Silurian and their rapid diversificationin the Pragian (especially if such diversification was notcoincident with the prominent radiation of durophagouspredators in the Prague Basin).

It may be pointed out that rutoceratoids represent a sin-gle new Early Devonian cephalopod clade with highlysculptured shells and shell outgrowths. Remaining newEarly Devonian clades exhibit clearly similar sculpture asanalogous Ordovician and Devonian cephalopod morpho-types (e.g., Nephriticeratidae versus Lechritrochocera-tidae, Spyroceratidae versus Kionoceratidae, Enti-moceratidae versus Trimeroceratidae). Consequently, theradiation of rutoceratoids (i.e., highly sculptured cephalo-pods) in the Early Devonian probably represents an effect(fabricational noise) of cephalopod faunal recovery afterthe Silurian-Devonian boundary Event rather than a radia-tion of durophagous predators.

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David H. Evans (Natural England, Peterborough) and ChristianKlug (Universität Zürich, Zürich) are deeply acknowledged formanuscript revision and valuable suggestions substantially improv-ing this paper. Many thanks to Radvan Horný (National Museum,Prague) for critical reading of the manuscript and for language cor-rections. Petr Budil (Czech Geological Survey) kindly gave access toBouška’s collection. The authors thank Jessica Cundiff (Museum ofComparative Zoology, Harvard) for providing the material fromŠáry’s collection used in this study. The contribution was supportedby the projects Kontakt (MEO8011), VaV DE08P04OMG002(Š. Manda) and GACR 205/09/0260 (V. Turek).

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AGASSIZ, L. 1847. An introduction to the study of Natural history,in a series of lectures delivered in the hall of the College of Phy-sicians and Surgeons. 58 pp. Greeley & McElrath, New York.

ARKELL, W.J., KUMMEL, B. & WRIGHT, C.W. 1957. MesozoicAmmonoidea, 80–437. In MOORE, R.C. (ed.) Treatise on In-vertebrate Paleontology, Part L. Mollusca 4. Geological Soci-ety of America & The University of Kansas Press, New York &Lawrence.

BARRANDE, J. 1848. Eine weitere Sendung von Cephalopodenaus den silurischen Schichten von Böhmen. Berichte überMittheilungen von Freunden der Naturwissenschaften in Wien4, 208–211.

BARRANDE, J. 1865–1877. Systême silurien du Centre de laBohême, Ière partie: Recherches Paléontologiques, vol. II,Classe de Mollusques, Ordre des Céphalopodes, 1865, ser. 6, pl.1–107; 1866, ser. 7, pl. 108–244; 1867, ser. 1, 712 pp.; 1868, ser.8, pl. 245–350; 1870, ser. 2, 266 pp., ser. 9, pl. 351–460; 1874,ser. 3, 804 pp.; 1877, ser. 4, 742 pp., ser. 5, 743 pp., Supplement1, 297 pp., Supplement 2, pl. 461–544. Prague & Paris.

BOUČEK, B. 1931. O některých nových bohatých nalezištích zka-menělin ve starším paleozoiku středních Čech. Věda přírodní 12,136–144.

BUDIL, P. & KOLÁŘ, P. 2004. Kainops chlupaci sp. n. from theLower Devonian (Zlichovian Stage) from the Barrandian area(Czech Republic). Journal of the Czech Geological Society49(3–4), 141–145.

CARLS, P., SLAVÍK, L. & VENEZUELA-RÍOS, J.I. 2008. Commentson the GSSP for the basal Emsian stage boundary: the need forredefinition. Bulletin of Geosciences 83(4), 383–390.DOI 10.3140/bull.geosci.2008.04.383

CHEN, J., LIU, G. & CHEN, T. 1981. Silurian nautiloid faunas ofcentral and southwestern China. Memoirs Nanjing Institute forGeology and Paleontology Academica Sinica 13, 1–104.

CHIRAT, R. & RIOULT, M. 1998. Occurrence of early post-hatch-ing Jurassic Nautilida in Normandy, France: palaeobiologicpalaeoecologic and palaeobiogeographic implications. Lethaia31, 137–148.

CHLUPÁČ, I. 1955. Stratigrafická studie o nejstarších devonskýchvrstvách Barrandienu. Sborník Ústředního ústavu geologic-kého, Oddíl geologický 21, 91–224.

���

����������� ������ �������������

CHLUPÁČ, I. 1957. Faciální vývoj a biostratigrafie středočeskéhospodního devonu. Sborník Ústředního ústavu geologického,Oddíl geologický 24, 369–485.

CHLUPÁČ, I. Ed. 1986. Barrandian-Moravian Karst 1986. A fieldtrip guidebook. 62 pp. Czech Geological Survey, Praha.

CHLUPÁČ, I. 1982. The Bohemian Lower Devonian Stages. Cou-rier Forschung Institut Senckenberg 55, 345–400.

CHLUPÁČ, I. 1983. Stratigraphical position of Barrande’spaleontological localities in the Devonian of Central Bohemia.Časopis pro mineralogii a geologii 28(3), 261–275.

CHLUPÁČ, I. 1998. Devonian, 101–133. In HAVLÍČEK, V., KŘÍŽ,J., KUKAL, Z. & ŠTORCH, P. 1998. Palaeozoic of the Bar-randian (Cambrian to Devonian). 183 pp. Český geologickýústav, Praha.

CHLUPÁČ, I. & KOLÁŘ, P. 2001. First homanolotid trilobites fromthe Devonian of Bohemia and their significance. Bulletin of theCzech Geological Survey 76(3), 179–186.

CHLUPÁČ, I. & KUKAL, Z. 1988. Possible global events and thestratigraphy of the Barrandian Palaeozoic (Cambrian–Devo-nian). Sborník geologických věd, Geologie 43, 83–146.

CHLUPÁČ, I. & ŠNAJDR, M. 1990. A remarkable Pragian trilobiteassemblage from the Barrandian. Věstník Ústředního ústavugeologického 64(3), 129–142.

DZIK, J. 1984. Phylogeny of the Nautiloidea. Paleontologia Po-lonica 45, 1–255.

DZIK, J. & KORN, D. 1992. Devonian ancestors of Nautilus.Paläontologische Zeitschrift 66(1–2), 81–98.

FAGERSTROM, J.A. 1961. The fauna of the Middle DevonianFormosa reef limestone of southwestern Ontario. Journal ofPaleontology 35(1), 1–48.

FLOWER, R.H. 1936. Cherry Valley cephalopods. Bulletin ofAmerican Paleontology 22(76), 1–96.

FLOWER, R.H. 1945. Classification of Devonian Nautiloids.American Midland Naturalist 33(3), 675–724.DOI 10.2307/2421185

FLOWER, R.H. 1947. Cayugoceras, an Upper Silurian cepha-lopod. American Midland Naturalist 37, 250–255.DOI 10.2307/2421653

FLOWER, R.H. 1949. New genera of Devonian nautiloids. Journalof Paleontology 23(1), 74–80.

FLOWER, R.H. 1952. The ontogeny of Centroceras with remarkson the phylogeny of the Centroceratidae. Journal of Paleontol-ogy 26, 519–528.

FLOWER, R.H. 1955. Saltations in nautiloid coiling. Evolution 9,244–260. DOI 10.2307/2405647

FLOWER, R.H. 1964. Nautiloid shell morphology. Memoir NewMexico Bureau of Mines and Mineral Resources 12, 1–234.

FLOWER, R.H. 1988. Progress and Changing Concepts inCephalopod and Particularly Nautiloid Phylogeny and Distri-bution, 17–24. In WIEDMANN, J. & KULLMANN, J. (eds)Cephalopods Present and Past. 766 pp. E. Schweizerbart’scheVerlagsbuchhandlung, Stuttgart.

FLOWER, R.H. in FLOWER, R.H. & KUMMEL, B. 1950. A classifica-tion of the Nautiloidea. Journal of Paleontology 24(5), 604–616.

FLOWER, R.H. & TEICHERT, C. 1957. The cephalopod orderDiscosorida. University of Kansas Paleontological Contribu-tions, Mollusca 6, 1–144.

FOERSTE, A.F. 1926. Actinosiphonate, Trochoceroid and othercephalopods. Bulletin of the Scientific Laboratories of DenisonUniversity 21, 285–384.

FOERSTE, A.F. 1930a. Port Byron and other Silurian cephalopods.Bulletin of the Scientific Laboratories of Denison University23, 1–110.

FOERSTE, A.F. 1930b. The color patterns of fossil cephalopodsand brachiopods, with notes on gastropods and pelecypods.Contribution from the Museum of Paleontology University ofMichigan 3(6), 109–150.

GNOLI, M. 1982. Lower Devonian orthocone cephalopods fromthe Iglesiente and Sulcis regions (Southwestern Sardinia).Bolletino della Società Paleontologica Italiana 21, 73–98.

GRABAU, W.A. 1910. Description of Monroe Fossils. MichiganGeological Survey Publication 2, 196–200.

HALL, J. 1879. Natural history of New York, Paleontology, vol. 5,part 2, containing descriptions of the Gastropoda, Pteropoda,Cephalopoda, Crustacea and Corals of the Upper Helderberg,Hamilton portage and Chemung groups. 362 pp. New YorkGeological Survey, New York.

HAVLÍČEK, V. & VANĚK, J. 1998. Pragian brachiopods, trilobites,and principal biofacies in the Prague Basin (Lower Devonian,Bohemia). Sborník geologických věd, Paleontologie 34,27–109.

HAVLÍČEK, V., VANĚK, J. & FATKA, O. 1994. Perunica micro-continent in the Ordovician (its position within the Mediterra-nean Province, series division, benthic and pelagic associa-tions). Sborník geologických věd, Geologie 46, 23–56.

HORNÝ, R. 1965. Corbuloceras gen. n., nový onkoceridní hlavo-nožec (Cephalopoda, Oncocerida) z českého siluru. ČasopisNárodního muzea, Oddíl přírodovědný 134(3), 132–137.

HORNÝ, R.J. 1995. Společenstvo gastropodů z loděnickýchvápenců (spodní devon, prag) na Branžovech u Loděnice.Časopis Národního muzea 164(1–4), 3–10.

HOUSE, M.R. 2002. Strength, timing, setting and cause of mid-Palaeozoic extinctions. Palaeogeography, Palaeoclimatology,Palaeoecology 181(1–3), 5–25.

HYATT, A. 1883–1884. Genera of fossil cephalopods. Proceed-ings of the Boston Society of Natural History 22, 273–338.

HYATT, A. 1894. Phylogeny of an Acquired characteristic. Pro-ceedings American Philosophical Society 32, 349–647.

HYATT, A. 1900. Cephalopoda, 502–592. In ZITTEL, K.A. &EASTMANN, C.R. (eds) Textbook of Palaeontology, vol. 1.MacMillan, Boston.

JANOUŠEK, V., HLADIL, J., FRÝDA, J., SLAVÍK, L. & ŠMÍD, J.2001. Strontium chemostratigraphy of carbonate sediments –pilot study of Silurian and Devonian brachiopods from thePrague Basin. Geolines 13, 68–69.

KATZER, F. 1895. Beiträge zur Palaeotologie des älteren Pa-laeozoicums in Mittelböhmen. Verlag der könig. BöhmischenGessellschaft der Wissenschaften 14, 1–17.

KŘÍŽ, J. 1998. Recurrent Silurian-Lowest Devonian CephalopodLimestones of Gondwanan Europe and Perunica. New YorkState Museum Bulletin 491, 183–198.

KŘÍŽ, J., JAEGER, H., PARIS, F. & SCHÖNLAUB, H.P. 1986. Přídolí– the fourth subdivision of the Silurian. Jahrbuch derGeologischen Bundesanstalt 129, 291–360.

��*

������ ����� �!���" #�$�% � &$�'���(����$������)*��������+,����������-����$���.

KOBLUK, D.R. & MAPES, R.H. 1989. The fossil record, functionand possible origins of shell color patterns in Paleozoic marineinvertebrates. Palaios 4, 63–85. DOI 10.2307/3514734

KODYM, O., BOUČEK, B. & ŠULC, J. 1931. Průvodce ku geo-logické exkursi do okolí Berouna, Koněprus a Budňan.Knihovna Státního geologického ústavu 15, 1–83.

KRÖGER, B. 2004. Large size sublethal injuries in Middle Ordovi-cian orthocerids. GFF 126, 311–316.

KRÖGER, B. 2008. Nautiloids before and during the origin ofammonoids in a Siluro-Devonian section in the Tafilalt, Anti-Atlas, Morocco. Special Papers in Paleontology 79, 1–112.

KUKAL, Z. & JAGER, O. 1988. Siliciclastic signal of the Variscanorogenesis; Devonian Srbsko Formation of Central Bohemia.Věstník Ústředního ústavu geologického 63(2), 65–80.

KUMMEL, B. 1964. Nautiloidea – Nautilida, 383–457. In MOORE,R.C. (ed.) Treatise on Invertebrate Paleontology, Part K, Mol-lusca 3, Cephalopoda. 519 pp. Geological Society of America &The University of Kansas Press, Boulder & Lawrence.

MANDA, Š. 2001. Some new or little known cephalopods from theLower Devonian Pragian carbonate shelf (Prague Basin, Bohe-mia) with remarks on Lochkovian and Pragian cephalopodevolution. Journal of the Czech Geological Society 46(3–4),269–286.

MANDA, Š. 2007. Late Silurian events and cephalopod extinctionsin the Prague Basin, 132–133. In Seventh International Sympo-sium Cephalopods Present and Past. Palaeontological Societyof Japan, Sapporo.

MANDA, Š. 2008. Palaecology and palaeogeographic relations ofthe Silurian phragmoceratids (Nautiloidea, Cephalopoda) ofthe Prague Basin (Bohemia). Bulletin of Geosciences 83(1),39–62. DOI 10.3140/bull.geosci.2008.01.039

MANDA, Š. & TUREK, V. In press. Minute Silurian oncoceridswith unusual colour patterns (Nautiloidea). Acta Paleonto-logica Polonica.

MILLER, A.K. 1932. New names for Devonian cephalopod hom-onym. American Journal of Science 24, 330–331.

NOVÁK, O. 1886. Zur Kenntnis der Fauna der Etage F - f1 in derPalaeozoischen Schichtengroupe Böhmens. Sitzungsberichteder Keiserlichen Böhmischen Gesellelschaft der Wissen-schaften 1886, 1–23.

PHILLIPS, J. 1841. Figures and descriptions of the Palaeozoic fos-sils of Cornwall, Devon, and west Somerset. 231 pp. Geologi-cal Survey of Great Britani and Ireland, London.

RAUP, D.M. 1966. Geometric analysis of shell coiling: generalproblems. Journal of Paleontology 40, 1178–1190.

RÖHLICH, P. 2007. Structure of the Prague Basin: The deforma-tion diversity and its causes (the Czech Republic). Bulletin ofGeosciences 82(2), 175–182.

RUEDEMANN, R. 1925. Some Silurian (Ontarian) faunas of NewYork. Bulletin of the New York State Museum 265, 5–133.

RUZHENTSEV, V.E., ZHURAVLEVA, F.A., BALASHOV, Z.G., BO-

GOSLOVSKY, B.I. & LIBROVICH, L.S. 1962. Osnovy Paleon-tologii, Moluski, Golovonogie. 438 pp. Nauka, Moscow.

RŮŽIČKA, R. 1941. Faunistické seznamy z Barrandienu zesouvrství gα’ (část II.) a ze dvou lokalit gγ. Věstník Královskéčeské společnosti nauk, 1–16.

SHIMANSKY, V.N. 1957. Sistematika i fylogenia otrjada Nau-

tilida. Bulleten Moskovskogo obshchestva ispytatelei prirody,Otdel geologicheskii 32, 105–120.

SIGNOR, P.W. & BRETT, C.E. 1984. The mid-Paleozoic precursorto the Mesozoic marine revolution. Paleobiology 10, 229.

STRIDSBERG, S. 1985. Silurian oncocerid cephalopods fromGotland. Fossils and Strata 18, 1–65.

STRIDSBERG, S. 1988. A Silurian cephalopod genus with a rein-forced frilled shell. Palaeontology 31(3), 651–663.

SWEET, W.C. 1964. Nautiloidea-Oncocerida, 277–319. InMOORE, R.C. (ed.) Treatise on Invertebrate Paleontology,Part K, Mollusca 3, Cephalopoda. 519 pp. Geological Societyof America & The University of Kansas Press, Boulder & Law-rence.

TEICHERT, C. 1939. Nautiloid Cephalopods from the Devonian ofWestern Australia. Journal of the Royal Society of West Aus-tralia 25, 103–121.

TEICHERT, C. 1964. Morphology of hard parts, 313–353. InMOORE, R.C. (ed.) Treatise on Invertebrate Paleontology,Part K, Mollusca. Geological Society of America, Lawrence.

TUREK, V. 1975. Genus Kosovoceras gen. n. in the Silurian ofCentral Bohemia. Sborník geologických věd, Paleontologie 17,7–42.

TUREK, V. 1976. Magdoceras gen. n. and Inclytoceras gen. n. fromthe Silurian of central Bohemia (Nautiloidea, Barrandeocerida).Časopis pro mineralogii a geologii 21(2), 137–145.

TUREK, V. 1990. Color patterns on Silurian and Devonian cepha-lopods of Central Bohemia, 81. Abstracts 3rd Symposium ofcephalopods: Present and past. Lyon.

TUREK, V. 2007. Systematic position and variability of the Devo-nian nautiloids Hercoceras and Ptenoceras from the PragueBasin (Czech Republic). Bulletin of Geosciences 82(1), 1–10.DOI 10.3140/bull.geosci.2007.01.1

TUREK, V. In press. Colour patterns in Lower Devonian cephalo-pods from the Barrandian Area: Taphony and taxonomy. ActaPalaeontologica Polonica 53.

WESTERMANN, G.E.G. 1998. Life Habits of Nautiloids, 263–298.In SAVAZZI, E. (ed.) Functional Morphology of the Inverte-brate Skeleton. John Wiley, London.

WHIDBORNE, G.F. 1890. A monograph of the Devonian Fauna ofthe South of England. Palaeontographical Society, Volume for1890, 47–154.

YOLKIN, E.A., KIM, A.I., WEDDIGE, K., TALENT, J.A. & HOUSE,M.R. 1997. Definition of the Pragian/Emsian Stage boundary.Episodes 20, 235–240.

ZHURAVLEVA, F.A. 1972. Devonskie nautiloidei. Otriad Disco-sorida. Trudy Paleontologicheskogo Instituta Akademii NaukSSSR 134, 1–320.

ZHURAVLEVA, F.A. 1974. Devonskie nautiloidei. Otriady Onco-ceratida, Tarphyceratida, Nautilida. Trudy Paleontologiches-kogo Instituta Akademii Nauk SSSR 142, 5–142.

ZHURAVLEVA, F.A. 1978. Devonskie nautiloidei. NadotriadOrthoceratoidea. Trudy Paleontologicheskogo Instituta Aka-demii Nauk SSSR 178, 1–224.

ZHURAVLEVA, F.A. 1996. Devonskie nautilidy severnych raionovRossii. Paleontologicheskij Zhurnal 1996(2), 16–24.

ZITTEL, K.A. 1900. Textbook of Palaeontology, vol. 1. 706 pp.Macmillan, New York.

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Only genera considered in this paper to be rutoceratoids are included.

Hyatt (1884, 1894)

Family Hercoceratidae Hyatt, 1884Ptyssoceras Hyatt, 1884Hercoceras Barrande, 1865Ptenoceras Hyatt, 1894

Family Rutoceratidae Hyatt, 1884Halloceras Hyatt, 1884Rutoceras Hyatt, 1884Adelphoceras Barrande, 1870Kophinoceras Hyatt, 1884

Family Discoceratidae Hyatt, 1894Trochoceras Barrande, 1848

Hyatt (1900)

Superfamily Ryticeratida Hyatt, 1900Family Halloceratidae Hyatt, 1900

Halloceras Hyatt, 1884Family Ryticeratidae Hyatt, 1900

Ryticeras Hyatt, 1900(= Rutoceras Hyatt, 1884)Cophinoceras Hyatt, 1884(= Kophinoceras Hyatt, 1884)

Superfamily Hercoceratida Hyatt, 1900Family Hercoceratidae Hyatt, 1884

Hercoceras Barrande, 1865Ptyssoceras Hyatt, 1884Ptenoceras Hyatt, 1894

Flower & Kummel (1950)

Order Rutoceratida Flower, 1950Family Rutoceratidae Hyatt, 1884

Rutoceras Hyatt, 1884Adelphoceras Barrande, 1870Casteroceras Flower, 1936Centrolitoceras Flower, 1945Diademoceras Flower, 1945Goldringia Flower, 1945Halloceras Hyatt, 1884Hercoceras Barrande, 1865Hindeoceras Flower, 1945Homoadelphoceras Foerste, 1926Ptenoceras Hyatt, 1894Pleuroncoceras Flower, 1945Ptyssoceras Hyatt, 1884Roussanoffoceras Foerste, 1925Trochoceras Barrande, 1848

Family Tetragonoceratidae Flower, 1945Nassauoceras Miller, 1932

Ruzhencev et al. (1962)

Order Oncocerida Flower, 1950Superfamily Ptenocerataceae Teichert, 1938

Family Ptenoceratidae Teichert, 1938Ptenoceras Hyatt, 1894Adelphoceras Barrande, 1870Homoadelphoceras Foerste, 1926

Order Nautilida Agassiz, 1847Suborder Rutoceratina Hyatt, 1884

Superfamily Rutocerataceae Hyatt, 1884Family Rutoceratidae Hyatt, 1884

Rutoceras Hyatt, 1884Casteroceras Flower, 1936Centrolitoceras Flower, 1945Diademoceras Flower, 1945Goldringia Flower, 1945Halloceras Hyatt, 1884Hercoceras Barrande, 1865Hindeoceras Flower, 1945Pleuroncoceras Flower, 1945Ptyssoceras Hyatt, 1884Roussanoffoceras Foerste, 1925Tetranodoceras Flower, 1936Trochoceras Barrande, 1848

Suborder Tainoceratina Hyatt, 1883Superfamily Tainoceratidae Hyatt, 1883

Family Tetragonoceratidae Flower, 1945Nassauoceras Miller, 1932

Kummel (1964)

Order Nautilida Agassiz, 1847Superfamily Tainocerataceae Hyatt, 1883

Family Rutoceratidae Hyatt, 1884Rutoceras Hyatt, 1884Adelphoceras Barrande, 1870Casteroceras Flower, 1936Centrolitoceras Flower, 1945Diademoceras Flower, 1945Goldringia Flower, 1945Halloceras Hyatt, 1884Hercoceras Barrande, 1865Hindeoceras Flower, 1945Homoadelphoceras Foerste, 1926Ptenoceras Hyatt, 1894Pleuroncoceras Flower, 1945Ptyssoceras Hyatt, 1884Roussanoffoceras Foerste, 1925Trochoceras Barrande, 1848

Family Tetragonoceratidae Flower, 1945Nassauoceras Miller, 1932

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Zhuravleva (1974)

Order Oncocerida Flower, 1950Family Ptenoceratidae Teichert, 1939

Ptenoceras Hyatt, 1894Adelphoceras Barrande, 1870Doleroceras Zhuravleva, 1972Homoadelphoceras Foerste, 1926Megaloceras Zhuravleva, 1974Ptyssoceras Hyatt, 1884Spanioceras Zhuravleva, 1974Trochoceras Barrande, 1848

Order Nautilida Agassiz, 1847Suborder Rutoceratina Hyatt, 1884

Superfamily Rutocerataceae Hyatt, 1884Family Rutoceratidae Hyatt, 1884

Rutoceras Hyatt, 1884Adeloceras Zhuravleva, 1974Alethynoceras Zhuravleva, 1974Anepheloceras Zhuravleva, 1974Aphyctoceras Zhuravleva, 1974Bastindoceras Zhuravleva, 1974Casteroceras Flower, 1936Capricornites Zhuravleva, 1974Centolitoceras Flower, 1945Diademoceras Flower, 1949Goldringia Flower, 1945Halloceras Hyatt, 1884Hercoceras Barrande, 1866Hindeoceras Flower, 1945Kophinoceras Hyatt, 1884Piratoceras Zhuravleva, 1974Pleuronoceras Flower, 1950Uloceras Zhuravleva, 1974Roussanoffoceras Foerste, 1925Tetranodoceras Flower, 1936

Family Tetragonioceratidae Flower, 1945Nassauoceras Miller, 1932

Dzik (1984)

Order Oncocerida Flower, 1950Family Rutoceratidae Hyatt, 1884

Rutoceras Hyatt, 1884 (= Goldringia Flower, 1945)?Ptenoceras Hyatt, 1894 (= Pleuronoceras Flower, 1950)Aphyctoceras Zhuravleva, 1974Capricornites Zhuravleva, 1974Casteroceras Flower, 1936?Halloceras Hyatt, 1884Hindeoceras Flower, 1945(= Centrolitoceras Flower, 1945)

Order Nautilida Agassiz, 1847Suborder Centroceratina Flower, 1950

Family Trochoceratidae Zittel, 1884Trochoceras Barrande, 1848

Hercoceras Barrande, 1865(= Adeloceras Zhuravleva, 1974; Spanioceras Zhurav-leva, 1974)Megaloceras Zhuravleva, 1974)Nassauoceras Miller, 1932?Doleroceras Zhuravleva, 1972?Ptenoceras Hyatt, 1894?Adelphoceras Barrande, 1870?Anepheloceras Zhuravleva, 1974?Halloceras Hyatt, 1884

This paper

Order Oncocerida Flower, 1950Superfamily Rutoceratoidea Hyatt, 1884

Family Parauloceratidae fam. nov.Parauloceras gen. nov. (Pragian–Emsian)Uloceras Zhuravleva, 1974 (Emsian)

Family Hercoceratidae Hyatt, 1884(= Ptenoceratidae Teichert, 1939)

Ptenoceras Hyatt, 1894 (Pragian–Eifelian)(= Doleroceras Zhuravleva, 1972)Adeloceras Zhuravleva, 1974 (Emsian)Anepheloceras Zhuravleva, 1974 (Emsian)Capricornites Zhuravleva, 1974 (Emsian)Centrolitoceras Flower, 1945 (Middle Devonian)Diademoceras Flower, 12949 (Emsian)Hercoceras Barrande, 1865 (Late Emsian–Eifelian)(= Bastindoceras Zhuravleva, 1974; Piratoceras Zhurav-leva, 1974; Spanioceras Zhuravleva, 1974; ?MegalocerasZhuravleva, 1974; Moneroceras Zhuravleva, 1996;?Nassauoceras Miller, 1932)Nozemoceras Zhuravleva, 1996 (Emsian)Otomaroceras gen. nov. (Pragian)Ptyssoceras Hyatt, 1884 (Pragian)Pleuronoceras Flower, 1950 (Middle Devonian)New unnamed genus (based on Rutoceras eospinosumZhuravleva, 1974, Emsian)

Family Rutoceratidae Hyatt, 1884(= Halloceratidae Hyatt, 1900; Ryticeratidae Hyatt, 1900;Adelphoceratidae Foerste, 1926)

Adelphoceras Barrande, 1870 (late Emsian)Aphyctoceras Zhuravleva, 1974 (Pragian–Givetian)Capricornites Zhuravleva, 1974 (Emsian)Casteroceras Flower, 1936 (Middle Devonian)Goldringia Flower, 1945 (Pragian–Givetian)Halloceras Hyatt, 1884 (Emsian–Givetian)Hindeoceras Flower, 1945 (Eifelian–Frasnian)Homoadelphoceras Foerste, 1926 (Late Emsian)Kophinoceras Hyatt, 1884 (Middle Devonian)Pseudorutoceras gen. nov. (Eifelian–Givetian)Rutoceras Hyatt, 1884 (Pragian–Givetian, ?early Frasnian)Tetranodoceras Flower, 1936 (Middle Devonian)

?Family Trochoceratidae Zittel, 1884Trochoceras Barrande, 1848 (Pragian)

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